Biomedical subjects

Shaolin Mu

Publications and source records attributed to Shaolin Mu.

3 recordsLinked to original sources

PubMed2007

Improvement in selectivity and storage stability of a choline biosensor fabricated from poly(aniline-co-o-aminophenol).

A choline biosensor was fabricated by using electrochemical doping to immobilize choline oxidase in poly(aniline-co-o-aminophenol) film that exhibits a good electric activity over a wide pH range. Using cyclic voltammetry, impedance measurement and scanning electron microscopy characterized the poly(aniline-co-o-aminophenol) film doped with choline oxidase. The amperometric detection of choline is based on the oxidation of the H2O2 enzymatically produced on the choline biosensor. The choline biosensor has a lower potential dependence. Thus, its operational potential was controlled at a low potential of 0.40 V (vs.SCE). The response current of the choline biosensor increases with increasing temperature from 277.1 to 308.1 K. An apparent activation energy of 30.8 kJ mol(-1) was obtained. The choline biosensor has a wide linear response range from 1x10(-7) to 1x10(-4) M choline with a correlation coefficient of 0.9999 and has a high sensitivity of 127 microA cm(-2), at 0.40 V and pH 8.0. The response time of the biosensor is 15-25 s, depending on the applied potentials. An apparent Michaelis constant and an optimum pH for the immobilized enzyme are 1.8 mM choline and 8.4, respectively, which are very close to those of choline oxidase in solution. The effect of selected organic compounds on the response of the choline biosensor was studied. Together, these findings show that the choline biosensor exhibits a better selectivity to interfering species and a better storage stability.

Alcohol Oxidoreductases↗

PubMed2005

Determination of hydrogen peroxide using amperometric sensor of polyaniline doped with ferrocenesulfonic acid.

The result of cyclic voltammetry shows that polyaniline doped with ferrocenesulfonic acid (PAnFc) can effectively catalyze the oxidation of hydrogen peroxide, so PAnFc is used as a sensor to determine the concentration of H2O2. Iron in the ferrocenesulfonic acid exists in two oxidation states: Fe2+ and Fe3+. They can reversibly oxidize and reduce between the Fe2+ and Fe3+ oxidation states, which play an important role in the catalytic oxidation of H2O2. The response current of the sensor depends on the pH, applied potential and temperature at a given concentration of H2O2. At optimum conditions, the sensor has a fast response to H2O2, good operational stability, a good linear response to H2O2 in the range from 4 to 64 microM, and a small temperature dependence of the response current.

Aniline Compounds↗

PubMed2005

Catechol sensor using poly(aniline-co-o-aminophenol) as an electron transfer mediator.

In this work, poly(aniline-co-o-aminophenol) (copolymer) was used as an electron transfer mediator in the electrochemical oxidation of catechol due to its reversible redox over a wide range of pH. The experimental results indicate that the anodic peak potential of catechol at the copolymer electrode is lower than that at the platinum electrode in a solution consisting of catechol and sodium sulfate with pH 5.0, and the activation energy for the electrochemical oxidation of catechol at the copolymer electrode is low (23.6 kJ mol(-1)). These are strong evidence for the electrocatalytic oxidation of catechol at the copolymer electrode. The -OH group on the copolymer chain plays an important role in the electron transfer between the copolymer electrode and catechol in the solution. Based on the catalytic oxidation, the copolymer is used as a sensor to determine the concentration of catechol. The response current of the sensor depends on the concentration of catechol, pH, applied potential and temperature. At 0.55 V (versus saturated calomel reference electrode (SCE)) and pH 5.0, the sensor has a fast response (about 10s) to catechol and good operational stability. The sensor shows a linear response range between 5 and 80 microM catechol with a correlation coefficient of 0.997. It was found that phenol and resorcinol cannot be oxidized at the copolymer electrode at potentials < or =0.55 V, so controlling the sensor potential affords a good way of avoiding the effect of phenol and resorcinol on the determination of catechol.

Aminophenols↗